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Mohammad Arif Ashraf, Abidur Rahman
Endosomal trafficking plays an important role in regulating plant growth and development both at optimal and stressed conditions. Cold stress response in Arabidopsis root is directly linked to inhibition of the endosomal trafficking of auxin efflux carriers. However, the cellular components that link cold stress and the endosomal trafficking remain elusive. By screening available endosomal trafficking mutants against root growth recovery response under cold stress, we identified GNOM, a SEC7 containing ARF-GEF, as a major modulator of cold response...
October 26, 2018: Plant Journal: for Cell and Molecular Biology
Kiril Mishev, Qing Lu, Bram Denoo, François Peurois, Wim Dejonghe, Jan Hullaert, Riet De Rycke, Sjef Boeren, Marine Bretou, Steven De Munck, Isha Sharma, Kaija Goodman, Kamila Kalinowska, Veronique Storme, Le Son Long Nguyen, Andrzej Drozdzecki, Sara Martins, Wim Nerinckx, Dominique Audenaert, Grégory Vert, Annemieke Madder, Marisa S Otegui, Erika Isono, Savvas N Savvides, Wim Annaert, Sacco De Vries, Jacqueline Cherfils, Johan Winne, Eugenia Russinova
Small GTP-binding proteins from the ADP-ribosylation factor (ARF) family are important regulators of vesicle formation and cellular trafficking in all eukaryotes. ARF activation is accomplished by a protein family of guanine nucleotide exchange factors (GEFs) that contain a conserved catalytic Sec7 domain. Here, we identified and characterized Secdin, a small-molecule inhibitor of Arabidopsis thaliana ARF-GEFs. Secdin application caused aberrant retention of plasma membrane (PM) proteins in late endosomal compartments, enhanced vacuolar degradation, impaired protein recycling, and delayed secretion and endocytosis...
October 2018: Plant Cell
Daniela Dietrich
Fresh water is an increasingly scarce resource for agriculture. Plant roots mediate water uptake from the soil and have developed a number of adaptive traits such as hydrotropism to aid water foraging. Hydrotropism modifies root growth to respond to a water potential gradient in soil and grow towards areas with a higher moisture content. Abscisic acid (ABA) and a small number of genes, including those encoding ABA signal transducers, MIZ2/GNOM, and the hydrotropism-specific MIZ1, are known to be necessary for the response in Arabidopsis thaliana, whereas the role of auxin in hydrotropism appears to vary depending on the plant species...
May 19, 2018: Journal of Experimental Botany
Saeko Kitakura, Maciek Adamowski, Yuki Matsuura, Luca Santuari, Hirotaka Kouno, Kohei Arima, Christian S Hardtke, Jirí Friml, Tatsuo Kakimoto, Hirokazu Tanaka
Membrane traffic at the trans-Golgi network (TGN) is crucial for correctly distributing various membrane proteins to their destination. Polarly localized auxin efflux proteins, including PIN-FORMED1 (PIN1), are dynamically transported between the endosomes and the plasma membrane (PM) in the plant cells. The intracellular trafficking of PIN1 protein is sensitive to the fungal toxin brefeldin A (BFA), which is known to inhibit guanine nucleotide exchange factors for ADP ribosylation factors (ARF GEFs) such as GNOM...
October 1, 2017: Plant & Cell Physiology
Kristoffer Jonsson, Yohann Boutté, Rajesh Kumar Singh, Delphine Gendre, Rishikesh P Bhalerao
During early seedling development, the shoot apical meristem is protected from damage as the seedling emerges from soil by the formation of apical hook. Hook formation requires differential growth across the epidermis below the meristem in the hypocotyl. The plant hormones ethylene and auxin play key roles during apical hook development by controlling differential growth. We provide genetic and cell biological evidence for the role of ADP-ribosylation factor 1 (ARF1)-GTPase and its effector ARF-guanine-exchange factors (GEFs) of the Brefeldin A-inhibited GEF (BIG) family and GNOM in ethylene- and auxin-mediated control of hook development...
May 2017: Plant Cell
Ruixi Li, Cecilia Rodriguez-Furlan, Junqi Wang, Wilhelmina van de Ven, Ting Gao, Natasha V Raikhel, Glenn R Hicks
The endomembrane system is an interconnected network required to establish signal transduction, cell polarity, and cell shape in response to developmental or environmental stimuli. In the model plant Arabidopsis thaliana , there are numerous markers to visualize polarly localized plasma membrane proteins utilizing endomembrane trafficking. Previous studies have shown that the large ARF-GEF GNOM plays a key role in the establishment of basal (rootward) polarity, whereas the apically (shootward) polarized membrane proteins undergo sorting via different routes...
January 2017: Plant Cell
Hongqiang An, Qiankun Zhu, Wei Pei, Jing Fan, Yi Liang, Yihui Cui, Nan Lv, Wanjun Wang
Dendrobium officinale Kimu et Migo has increased many researchers' interest for its high medical and horticultural values and the molecular mechanism of its protocorm development remains unclear. In this study, 19 genes from 26 most stably expressed genes in whole transcriptome of protocorms and 5 housekeeping genes were used as candidate reference genes and screened with 4 application softwares (geNorm, NormFinder, BestKeeper and RefFinder). The results showed that a few reference genes could effectively normalize expression level of specific genes in protocorm development and the optimal top 2 reference genes were ASS and APH1L...
2016: PloS One
Chadin Kulsing, Andras Z Komaromy, Reinhard I Boysen, Milton T W Hearn
This study documents the use of an integrated approach, involving on-line hydrophobic interaction chromatography interfaced with Small Angle X-ray Scattering (HIC-SAXS) measurements, to monitor the conformational status of proteins immediately upon elution from a chromatographic column operated at different temperatures. Moreover, this approach provides an additional avenue to interrogate the changes in protein shape that may occur across the eluted chromatographic peak. To this end, radii of gyration were extrapolated from the Guinier approximation with the HIC-SAXS data, whilst pair distribution functions and bead model simulations were generated by using the indirect transform program GNOM and ab initio reconstruction with GASBOR to provide further insight into protein conformational changes that occur during hydrophobic interaction chromatography...
October 21, 2016: Analyst
Pusadee Sri-aroon, Phiraphol Chusongsang, Yupa Chusongsang, Yanin Limpanont, Pornpimol Surinthwong, Khamsing Vongphayloth, Paul T Brey
We conducted a malacological investigation in four districts of the Nam Theun 2 (NT2) hydroelectric dam project area, Khammouane Province, central Lao PDR (Nakai, Gnommalath, Mahaxai and Xe Bang Fai), after the first and second years of full operation in March 2010 and November 2011 to determine health risks for humans. A total 10,863 snail specimens (10 families/23 species) from 57 sampling stations and 12,902 snail specimens (eight families/21 species) from 66 sampling stations were collected in 2010 and 2011, respectively...
September 2015: Southeast Asian Journal of Tropical Medicine and Public Health
Adriana Jelínková, Karel Müller, Markéta Fílová-Pařezová, Jan Petrášek
BACKGROUND: Processes of anterograde and retrograde membrane trafficking play an important role in cellular homeostasis and dynamic rearrangements of the plasma membrane (PM) in all eukaryotes. These processes depend on the activity of adenosine ribosylation factors (ARFs), a family of GTP-binding proteins and their guanine exchange factors (GEFs). However, knowledge on the function and specificity of individual ARF-GEFs for individual steps of membrane trafficking pathways is still limited in plants...
2015: BMC Plant Biology
Dae Hwa Yoon, Sang Sook Lee, Hyun Ji Park, Jae Il Lyu, Won Seog Chong, Jang Ryol Liu, Beom-Gi Kim, Jun Cheul Ahn, Hye Sun Cho
AtCYP19-4 (also known as CYP5) was previously identified as interacting in vitro with GNOM, a member of a large family of ARF guanine nucleotide exchange factors that is required for proper polar localization of the auxin efflux carrier PIN1. The present study demonstrated that OsCYP19-4, a gene encoding a putative homologue of AtCYP19-4, was up-regulated by several stresses and showed over 10-fold up-regulation in response to cold. The study further demonstrated that the promoter of OsCYP19-4 was activated in response to cold stress...
January 2016: Journal of Experimental Botany
Andras Z Komaromy, Chadin Kulsing, Reinhard I Boysen, Milton T W Hearn
Key requirements of protein purification by hydrophobic interaction chromatography (HIC) are preservation of the tertiary/quaternary structure, maintenance of biological function, and separation of the correctly folded protein from its unfolded forms or aggregates. This study examines the relationship between the HIC retention behavior of hen egg white lysozyme (HEWL) in high concentrations of several kosmotropic salts and its conformation, assessed by circular dichroism (CD) spectroscopy. Further, the physicochemical properties of HEWL in the presence of high concentrations of ammonium sulfate, sodium chloride and magnesium chloride were investigated by small angle X-ray scattering (SAXS) at different temperatures...
March 2015: Biotechnology Journal
Siamsa M Doyle, Ash Haeger, Thomas Vain, Adeline Rigal, Corrado Viotti, Małgorzata Łangowska, Qian Ma, Jiří Friml, Natasha V Raikhel, Glenn R Hicks, Stéphanie Robert
Spatial regulation of the plant hormone indole-3-acetic acid (IAA, or auxin) is essential for plant development. Auxin gradient establishment is mediated by polarly localized auxin transporters, including PIN-FORMED (PIN) proteins. Their localization and abundance at the plasma membrane are tightly regulated by endomembrane machinery, especially the endocytic and recycling pathways mediated by the ADP ribosylation factor guanine nucleotide exchange factor (ARF-GEF) GNOM. We assessed the role of the early secretory pathway in establishing PIN1 polarity in Arabidopsis thaliana by pharmacological and genetic approaches...
February 17, 2015: Proceedings of the National Academy of Sciences of the United States of America
Meng Li, Fred D Sack
Crucifer shoots harbor a glucosinolate-myrosinase system that defends against insect predation. Arabidopsis thaliana myrosinase (thioglucoside glucohydrolase [TGG]) accumulates in stomata and in myrosin idioblasts (MIs). This work reports that the basic helix-loop-helix transcription factor FAMA that is key to stomatal development is also expressed in MIs. The loss of FAMA function abolishes MI fate as well as the expression of the myrosinase genes TGG1 and TGG2. MI cells have previously been reported to be located in the phloem...
October 2014: Plant Cell
Satoshi Naramoto, Marisa S Otegui, Natsumaro Kutsuna, Riet de Rycke, Tomoko Dainobu, Michael Karampelias, Masaru Fujimoto, Elena Feraru, Daisuke Miki, Hiroo Fukuda, Akihiko Nakano, Jiří Friml
GNOM is one of the most characterized membrane trafficking regulators in plants, with crucial roles in development. GNOM encodes an ARF-guanine nucleotide exchange factor (ARF-GEF) that activates small GTPases of the ARF (ADP ribosylation factor) class to mediate vesicle budding at endomembranes. The crucial role of GNOM in recycling of PIN auxin transporters and other proteins to the plasma membrane was identified in studies using the ARF-GEF inhibitor brefeldin A (BFA). GNOM, the most prominent regulator of recycling in plants, has been proposed to act and localize at so far elusive recycling endosomes...
July 2014: Plant Cell
Inês C R Barbosa, Melina Zourelidou, Björn C Willige, Benjamin Weller, Claus Schwechheimer
The directed cell-to-cell transport of the phytohormone auxin by efflux and influx transporters is essential for proper plant growth and development. Like auxin efflux facilitators of the PIN-FORMED (PIN) family, D6 PROTEIN KINASE (D6PK) from Arabidopsis thaliana localizes to the basal plasma membrane of many cells, and evidence exists that D6PK may directly phosphorylate PINs. We find that D6PK is a membrane-bound protein that is associated with either the basal domain of the plasma membrane or endomembranes...
June 23, 2014: Developmental Cell
Heather E McFarlane, Yoichiro Watanabe, Weili Yang, Yan Huang, John Ohlrogge, A Lacey Samuels
Lipid secretion from epidermal cells to the plant surface is essential to create the protective plant cuticle. Cuticular waxes are unusual secretory products, consisting of a variety of highly hydrophobic compounds including saturated very-long-chain alkanes, ketones, and alcohols. These compounds are synthesized in the endoplasmic reticulum (ER) but must be trafficked to the plasma membrane for export by ATP-binding cassette transporters. To test the hypothesis that wax components are trafficked via the endomembrane system and packaged in Golgi-derived secretory vesicles, Arabidopsis (Arabidopsis thaliana) stem wax secretion was assayed in a series of vesicle-trafficking mutants, including gnom like1-1 (gnl1-1), transport particle protein subunit120-4, and echidna (ech)...
March 2014: Plant Physiology
Jingzhe Guo, Jun Wei, Jian Xu, Meng-Xiang Sun
In plants, active transport of auxin plays an essential role in root development. Localization of the PIN1 auxin transporters to the basal membrane of cells directs auxin flow and depends on the trafficking mediator GNOM. GNOM-dependent auxin transport is vital for root development and thus offers a useful tool for the investigation of a possible tissue-specific response to dynamic auxin transport. To avoid pleiotropic effects, DEX-inducible expression of GNOM antisense RNA was used to disrupt GNOM expression transiently or persistently during embryonic root development...
March 2014: Journal of Experimental Botany
Teppei Moriwaki, Yutaka Miyazawa, Nobuharu Fujii, Hideyuki Takahashi
Plant roots exhibit tropisms in response to gravity, unilateral light and moisture gradients. During gravitropism, an auxin gradient is established by PIN auxin transporters, leading to asymmetric growth. GNOM, a guanine nucleotide exchange factor of ARF GTPase (ARF-GEF), regulates PIN localization by regulating subcellular trafficking of PINs. Therefore, GNOM is important for gravitropism. We previously isolated mizu-kussei2 (miz2), which lacks hydrotropic responses; MIZ2 is allelic to GNOM. Since PIN proteins are not required for root hydrotropism in Arabidopsis, the role of GNOM in root hydrotropism should differ from that in gravitropism...
February 2014: Plant Science: An International Journal of Experimental Plant Biology
Hirokazu Tanaka, Tomasz Nodzyłski, Saeko Kitakura, Mugurel I Feraru, Michiko Sasabe, Tomomi Ishikawa, Jürgen Kleine-Vehn, Tatsuo Kakimoto, Jiři Friml
Correct positioning of membrane proteins is an essential process in eukaryotic organisms. The plant hormone auxin is distributed through intercellular transport and triggers various cellular responses. Auxin transporters of the PIN-FORMED (PIN) family localize asymmetrically at the plasma membrane (PM) and mediate the directional transport of auxin between cells. A fungal toxin, brefeldin A (BFA), inhibits a subset of guanine nucleotide exchange factors for ADP-ribosylation factor small GTPases (ARF GEFs) including GNOM, which plays a major role in localization of PIN1 predominantly to the basal side of the PM...
April 2014: Plant & Cell Physiology
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